6e446cb7ad
The web source section's visibility was bound to SelectedElement.Type via a converter, but WebcamSceneConfig has no Type property — the WPF binding path didn't resolve correctly and the section leaked through. Added IsWebSource virtual property to SceneElement (mirrors existing IsWebcam pattern), overridden in Source to return Type == SourceType.WebSource. Section visibility now binds directly to SelectedElement.IsWebSource via BoolToVis. 1c of 7-issue polish batch. 207 tests, 0 warnings.